1. Field of the Invention
The invention relates to a process for the synthesis of .alpha.-[(dialkylamino)substituted methylene]-.beta.-oxo-(substituted)propanenitrile compounds and to novel substituted isoxazole compounds useful as intermediates in the process.
2. Description of the Prior Art
The .alpha.-[(dialkylamino)substituted-methylene]-.beta.-oxo-(substituted)prop anitrile compounds are important intermediates for the preparation of therapeutic aryl and heteroaryl [7-(aryl and heteroaryl)pyrazolo(1,5-a)-pyrimidin-3-yl]methanone compounds which are useful as anxiolylic, antiepileptic, sedative-hypnotic and skeletal muscle relaxant agents. The aryl and heteroaryl [7-(aryl and hetroaryl)-pyrazolo [1,5-a]pyrimidin-3-yl]methanone compounds and uses for such compounds are described in U.S. Pat. No. 4,521,422, the contents of which are incorporated by reference.
In U.S. Pat. No. 4,900,836, the contents of which are incorporated by reference, a series of reactions in which the .alpha.-[(dialkylamino)substituted methylene]-.beta.-oxo-(substituted)propanenitrile compounds are utilized to produce the [7-(alkyl and hetroaryl)pyrazolo (1,5-a)-pyrimidin-3-yl]methanone compounds is described. This reference also describes the synthesis of the .alpha.-[(dialkylamino) substituted methylene]-.beta.-oxo-(substituted) propanenitrile compounds via the reaction of a substituted acetonitrile with a dimethylformamide dimethylacetal.
It has now been found that .alpha.-[(dialkylamino) substituted methylene].beta.-oxo-(substituted) propane nitrile compounds may be advantageously synthesized via reaction of a substituted isoxazole with a dialkylamide dimethylacetal. The use of substituted isoxazole compounds in the production of .alpha.-[(dialkylamino)substituted methylene]-.beta.-oxo(substituted)propanenitrile compounds has not been taught nor suggested by the art.
Certain substituted isoxazole compounds and their synthesis are known. For example, 5-(2,3,4,5-tetrafluorophenyl)-isoxazole (Chem. Abst. Registry No. 110985-65-4), 5-(2,4-dichloro-5-fluorophenyl) isoxazole (Registry No. 103318-74-6), 5-(2,3,-dichloro-phenyl) isoxazole (Registry No. 76344-98-4), 5-(5-nitro-2-furyl)-isoxazole (Registry No. 32332-91-5), 5-(4-methylphenyl)-isoxazole (Registry No. 7064-35-9), 5-(m -chloro phenyl) isoxazole (Registry No. 7064-34-8), 5-(m-bromo phenyl) isoxazole (Registry No. 7064-33-7), 5-(p-chloro-phenyl) isoxazole (Registry No. 7064-32-6), 5-(p-bromo phenyl) isoxazole (Registry No. 7064-31-5), N-[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]-2-5-isoxazolyl)-3-thiophe nesulfonamide (Registry No. 103118-33-8), 3-hydroxy-4-(5-isoxazolyl)-2(5H)-foranone (Registry No. 84-608-81-1) and 5-phenyl isoxazole (Registry No. 1006-67-3) are known. Other substituted isoxazole compounds including those claimed herein are not known.